16 Under what condition should the operator of a small UA establish scheduled maintenance protocol?
A. When the manufacturer does not provide a maintenance schedule.
If the manufacturer does provide a maintenance schedule or manual, you would be advised to follow their procedures. It is not mandatory, but in case of an accident it would demonstrate that you do properly maintain your aircraft.
Formal maintenance procedures or record-keeping is not required for Part 107 aircraft in Part 43 (Maintenance) or Part 107 rules.
This is correct.
Why is this the correct answer, even if the rules don't require a scheduled maintenance protocol?
FAA AC 107-2 states:
188.8.131.52 If there are no scheduled maintenance instructions provided by the sUAS manufacturer or component manufacturer, the operator should establish a scheduled maintenance protocol. This could be done by documenting any repair, modification, overhaul, or replacement of a system component resulting from normal flight operations, and recording the time-in-service for that component at the time of the maintenance procedure. Over time, the operator should then be able to establish a reliable maintenance schedule for the sUAS and its components.
Advisory circulars are advisory and are not rules. They are usually good advice and the responsible pilot should follow the guidelnes in the AC.